(a) Who may make.— An individual of sound mind may make a living will governing the initiation, continuation, withholding or withdrawal of life-sustaining treatment if the individual:

1. (1) is 18 years of age or older;
2. (2) has graduated from high school;
3. (3) has married; or
4. (4) is an emancipated minor.

(b) Requirements.— A living will shall be:

1. (1) dated and signed by the principal by signature or mark or by another individual on behalf of and at the direction of the principal if the principal is unable to sign but specifically directs another individual to sign the living will; and
2. (2) witnessed by two individuals, each of whom is 18 years of age or older.

(c) Witnesses.—

1. (1) An individual who signs a living will on behalf of and at the direction of a principal may not witness the living will.
2. (2) A health care provider and its agent may not sign a living will on behalf of and at the direction of a principal if the health care provider or agent provides health care services to the principal.